This invention relates to fuel cells and, more particularly, to cells which consume gaseous or liquid fuels and produce electrical energy.
An advantageous full cell for energy conversion is described in my U.S. Pat. No. 4,863,813. In a cell of the type described therein, a hydrogen-containing material at room temperature, such as a gaseous mixture of hydrogen and oxygen, is directly coverted to direct-current electrical energy and the only reaction product is water.
In one specific illustrative such cell, a submicrometer-thick gas-permeable ionically conducting membrane made of pseudoboehmite is deposited on an electrode that comprises a platinized impermeable substrate. A layer, of platinum for example, is deposited on the top surface of the membrane to form the second electrode of the cell. The second electrode is porous enough to allow the gas mixture to pass into the membrane.
For a hydrogen/air mixture, such a cell provides useful current at an output voltage as large as about one volt, independent of the ratio of hydrogen to air for hydrogen&gt;50%. While the voltage and current provided by the basic cell are adequate for many applications of practical interest, I recognized that it would be desirable to try to devise a compact version of the basic cell that would be capable of providing higher current and power. Such a version, particularly if it were adapted to be made by low-cost continuous fabrication techniques, would significantly increase the applications for which the cell would be regarded as an attractive energy source.